1. Field of the Invention
The present invention relates to a driving method that can optimally drive a galvano scanner using a small and inexpensive system configuration, and to a galvano scanner system and driver for driving a galvano scanner using the driving method.
2. Description of the Related Art
To drive a galvano scanner (analog input/output type) in an arbitrary drive pattern, a drive command must be fed from an external command generator to its scanner driver in real time. The command generator is configured with a function generator, or a personal computer and a DA converter.
When the galvano scanner is driven from a certain position A to a target position B, for example, the value of a command voltage fed to the scanner driver (analog driver) must be changed from a command voltage value a corresponding to the position A to a command voltage value b corresponding to the position B. The command voltage that is output from the command generator is merely changed to the value b that corresponds to the final target position B. A path from the position A to the position B and arrival time must therefore be set by adjusting the scanner driver.
When the difference between the command voltage values a and b is large, the scanner driver must be adjusted so that the galvano scanner can be driven without an increase in an overshoot amount. FIG. 4A is a diagram showing the command input and the actual movement of the galvano scanner after the scanner driver has been adjusted so that overshooting does not occur. FIG. 4B is a diagram showing the command input and the scanner movement when overshooting has occurred without adjustment. As is apparent from the diagrams, when adjustment is made to eliminate overshooting, a lengthy amount of time is required until settling is completed. To avoid this situation, a method is commonly adopted whereby adjustments are made so as to input a command input waveform provided with a gradient from the command generator to the scanner driver and to optimize the scanner driver to the command input waveform when moving from the command voltage value a to b. FIG. 4C shows the actual movement of the scanner with respect to the command input having the gradient.
However, a command generator that is capable of generating such a command input waveform requires a function generator, special-purpose controller, PC, DA converter, and other high-function hardware, which leads to a larger, more expensive galvano scanner drive system.
Due to differences in service equipment and the like, it is possible that the command input waveform that is set in the command generator by the user may not necessarily match the input waveform from the command generator that was envisioned when adjusting the scanner driver. When the command input waveform that is input to the scanner driver is offset with respect to the input waveform that was envisioned at the time of the adjustment, vibrations and other unstable actions may be generated in the scanner, and stable driving and high-speed driving of the scanner may be compromised.
In view of the above, a main object of the present invention is to provide a driving method that can optimally drive a galvano scanner using a small and inexpensive system configuration, and to provide a galvano scanner system and driver.